Alkylation of benzene with propylene in the presence of ticl4 and alkyl aluminum sesquichloride



United States Patent ALKYLATIGN 0F BENZENE WITH PRGPYLENE IN THE PRESENCE 0F TiCl AND ALKYL ALU- MINUM ESQUICHLORHDE Russell G. Hay, Gibsonia, Leo F. Meyer, Pittsburgh, and Charies M. Seiwitz, Pitcairn, Pa, assignors to Gulf Research 8r Development Company, llittsburgh, Pa., a corporation of Deiavvare No Drawing. Filed Dec. 1, 1959, Ser. No. 856,349

4 Claims. (Cl. 260-671) This invention relates to a process for preparing an alkyl aromatic.

Alkyl aromatics are prepared in accordance with the process of this invention by reacting an alkylatable aromatic hydrocarbon with an olefin in the presence of a catalyst mixture containing an organo aluminum halide and a heavy metal halide at a temperature of at least about 55 C. By operating in accordance with such process alkyl groups are obtained on the aromatic hydrocarbon having the same number of carbon atoms as the aikylating olefin.

Any alkylatable aromatic hydrocarbon can be employed in the reaction, Whether it be solid or liquid, mononuclear, dinuclear or polynuclear, substituted or unsubstituted. Among the mononuclear allcylatable aromatic compounds which are preferred are benzene and substituted benzes containing as substituents from one to three alkyl radicals having from one to 20 carbon atoms, preferably from one to 10 carbon atoms. Among the dinuclear alkylatable aromatic compounds which are preferred are naphthalene and substituted naphthalenes containing as substituents from one to 4 alkyl radicals having from one to 20 carbon atoms, preferably from one to 10 carbon atoms. Examples of alkylatable aromatic compounds which can be employed are benzene, toluene, ethylbenzene, xylenes, tetralin, cumene, diisopropylbenzenes, n-octylbenzene, 2-phenyl-4-ethyloctadecane, naphthalene, isopropylnaphthalenes, diisopropylnaphthalenes, 1-ethyl-6-isobutylnaphthalene, 1,2,4 triisopropylbenzene, phenanthrene, etc. In the event the alkylatable aromatic compound is normally liquid, no extraneous solvent need be employed in the reaction. With a normally solid alkylatable hydrocarbon an inert solvent such as heptane, normai octane, isooctane, etc., can be employed.

While olefins having from two carbon atoms and up to 30 carbon atoms can be employed in the alkylation reaction, olefins having from three to 20 carbon atoms are preferred. Examples of olefins which can be employed are ethylene, propylene, isobutylene, butene-l, cisbutene-2, trans-butene-Z, pentene-l, cyclopentene, cyclohexene, cycloheptene, 4-methylcyclooctene, Z-methylbutene-l, Z-methylbutene-Z, 3-methylbutene-l, cis-pentene-Z, transpentene-Z, hexene-l, cis-hexene-Z, trans-hexene-2, 5,6-dimethylheptene-1, tetrapropylene, pentadecene-l, 6- cyclohexyldodecene- 1, 4-n-nonyldodecene-1, n-tetracosene-l, n-heptacosene-l, 13-cyclopentylpentacosene, etc.

The amount of olefin which need be present at any moment during the reaction can be of course be small. While the total amount of olefin which will be required for the reaction can be added to the reaction Zone initially with the alkylatable aromatic compound this is not preferred because of the tendency of some of the olefin to polymerize. Desirably a small amount of olefin is added to the reaction zone as the reaction progresses and until reaction ceases. The total amount of olefin consumed will of course vary with the alkylatable aromatic compound and olefin employed, the pressure, temperature, reaction time, catalysts, etc. In general the total amount of olefin can be at least about 0.2 mol, but preferably about one to about 4 mols, per mol of alkylatable aromatic compound.

3,129,255 Patented Apr. 14, 1964 The organo aluminum halide which forms one of the active agents in the catalyst system employed can be defined by the formula R AlX wherein R can be an arcmatic radical such as phenyl, tolyl, xylyl, etc.; or an alkyl group having from one to 10 carbon atoms, preferably from one to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, isobutyl, normal butyl, etc.; X is a halogen atom selected from the group consisting of fluorine, chlorine, bromine and iodine; and a and b are values from one to two. Examples of organo aluminum halides which can be employed are ethylaluminum sesquichloride, methylaluminum sesquichloride, ethylaluminum sesquibromide, isobutylaluminum sesquichloride, diethylaluminum chloride, ethylaluminum sesquifiuoride, n-butylaluminum dibromide, decylaluminum sesquichloride, methylaluminum sesquiiodide, etc.

The heavy metal halide which is employed in conjunction with the organo aluminum halide as the second active agent in the catalyst system is critical in order to obtain the desired alkylation reaction of this invention. The metallic portion thereof must be selected from group IVB of the periodic table, that is, titanium, zirconium and hafnium. Thus a titanium halide, such as titanium tetrachloride (TiCl zirconium chloride (ZrCl and hafnium chloride (HfCl can be employed with the organo aluminum halide and excellent results will be obtained.

We have found that excellent results Will be obtained by carrying out the alkylation reaction of this invention using the heavy metal halide and organo aluminum halide in a molar ratio of about one to one to about nine to one, preferably about three to one to about four to one. The total amount of catalyst employed is not critical, although the amount thereof has a pronounced affect on the extent of alkylation and the position assumed by the alkyl groups on the alkylatable aromatic compound. Thus the total amount of catalyst required must be at least about 0.1 millimol of catalyst per mol of alkylatable aromatic compound, preferably about one to about 10 millimols of catalyst per mol of alkylatable aromatic compound.

The reaction pressure is not critical and can be varied over a wide range. Since the catalyst is in the liquid phase, the alkylatable aromatic desirably is also in the liquid phase. In order, therefore, to contact the alkylatable aromatic at the high temperatures which have been found necessary for the alkylation reaction of this invention, elevated pressures are thus required. With higher boiling alkylatable aromatics, of course, lower pressures can be employed. Thus the pressure can be from about atmospheric to about 500 pounds per square inch gauge or higher.

The temperature required to obtain the alkyl aromatic in accordance with the process of this invention is critical. In the event a mononuclear aromatic compound, such as benzene or substituted benzene, is employed as charge the temperature must be at least about 55 C., preferably from about to about C. In some cases temperatures in excess of 130 C., for example up to about 220 C., can advantageously be employed. In the event a dinuclear or polynuclear compound such as naphthalene is employed as charge the temperature must be at least about C., preferably about to about 200 C.

Reaction time can be of short duration and can be controlled in any suitable manner. Since the reaction is exothermic, the temperature and contact time thereof can also be controlled by the rate of addition of olefin to the alkylatable aromatic compound. An additional advantage resulting from the addition of olefin to the alkylata'ole aromatic compound is that olefin polymerization is thereby inhibited. Thus a reaction time of at least 3,1 3 about 5 minutes, preferably about one to about 4 hours is suitable.

After the desired reaction has been completed, the catalyst is deactivated and further reaction terminated in a catalyst consisting of 1.11 millimols of ethyl aluminum sesquichloride per mol of toluene and 3.32 millimols of titanium tetrachloride per mol of toluene. The run was carried out over a period of 3 hours at a temperaany convenient manner, for example, by hydrolyzing the 5 ture of 140 C. and an initial pressure of 120 pounds same with a compound containing an active hydrogen per square inch gauge. 890 grams of product were resuch as water or methanol. The products can be recovered, of which 90 percent by weight was tr1isopropylcm iefied by the sunplg elpfitillent fif distilllatilpn. f tolgene, 7 percent1 diisopropyltoluene, 2 percent cymenc e process can e urt er 1 ustrate y re erence an one percent to uene. to the following examples. In each of the examples 1 Exam le 20 whose data are tabulated below in Table I the alkylatable p compound was benzene and the ol fin r l I hI\laphthalene was also alkylated in accordance wlth general 352 grams of benzene were placed in a flask hav- 1 e process of this invention. Thus one mol of naphing an inert atmosphere. The designated amount of t al was placed in an autoclave having an inert atcatalyst Was then added and the system pressured to 15 mosphere. 280 cubic centimeters of heptane were then about 150 pounds per square inch gauge with pro ylene. added to the autoclave, followed by the addition of 0.80 The reaction was permitted to proceed until the pres- Cc. of ethyl alum num sesquichloride and 3.28 cc. of sure was reduced to about 80 pounds per square inch t1tan1um .tetrachlonde. The autoclave was then heated gauge, at which point the system was again pressured to 80 C. while stirring and propylene pressured in until with propylene to 150 pounds per square inch pressure. 20 a pressure of 120 pounds per square inch gauge was at- This procedure was repeated for the designated time. At tained. Heating was continued but no reaction occurred the end of the reaction period the catalyst was deactivuntil the temperature was raised to 160 C. The temated by hydrolyzing the same with methanol and the perature was increased to a maximum of 210 C. As individual components recovered by distillation. the pressure decreased below 120 pounds per square inch TABLE I Grns. Percent by Weight in Product of- Reuc- Prod. Catalysts, Millimols per M01 01 tion Temp., Including Example Benzene Time C. Unre- 1,2,4,5- 1,3,5- 1,2,4- Dllsohrs. acted tctraisotriis0- trilso- Cumcne propyl- Ben- Polymer Benzene propylpropylpropylbenzene zone benzene benzene benzene 0.735 1111150---- 1.48 T1011 4 44 420 0 0 0 2 0 s2 10 0.735 Mason 1.48 ZrCh... 4 42 494 2 1.0 1.0 4 2 07 2:; 1.11 MASC. 1.11 T1011 4 130 800 12 G 15 24 23 19 a 0.735 MASC 1.4% T1011... 4 130 850 35 16 12 22 2 0.222 Mason" 1.094 T1014" 4 120 570 10 6 25 20 25 6 a 0.553 MASO 1.66 T1011. 4 60-70 620 1.0 1.0 6 7 40 1.11 EASC 3.32 T1011. 2 82 56s 6 4 5 2s 10 23 23 0.553 MASO 1551 1011. 4 120 925 50 33 2 0 0 0 15 0.553 EASG 1.55 T1011. 4 125 1,150 50 0 0 4 2 0 0553511150.--- 1.00 T1014. 4 130 940 20 20 s 11 5 2 0.553 EASC 1 130 1, 000 40 1.0 2 2 1. 0 4 0. 2% 125 955 41 25 11 3 5 2 14 1. 2% 130 1,100 30 42 0 0 5 2 21 as .2 3 a a a 1 1 2:: 0. 0. 0 1.66ZrAcA. 1 105 352 0 0 0 0 0 0 0.553 E1150--." 1.66 Ti[OC;H1]1 1 352 0 0 0 0 0 100 0 In Table I above MASC refers to methyl aluminum gauge more propylene was charged to the autoclave. sesquichloride, EASC to ethyl aluminum sesquichloride, After a period of 4 hours the temperature dropped to IBASC to isobutyl aluminum sesquichloride, ZrAcA to 100 C., after which the autoclave was cooled and dczirconium acetonyl acetonate and Ti[OC l-I to titanium gassed. The liquid product was filtered to remove cattetraisoprrgpoxide. It dean be seen frombtlhe alyst residultle 2111nd plasseld througlh a 1column pf aglmina Table I t at runs ma e at temperatures e ow to remove ig mo ecu ar weig t po ymer oi s. vapowere ineffective for purposes of this invention and that ration of the heptane solvent left behind a yellow pasty the deglned helzavyllmgtais nfiust be deinhployltled 1thei; resfilue containilng 1,3,iJ-tjtraisopropylgiaphthglene as halide orrn. t w'l e urt er note at t e a (y ate We as some po ymer oi. yield 0 a out 5 percent product in each instance contained alkyl groups having by weight, based on the naphthalene charge, of the 1,3, the same number of carbon atoms as the alkylating 5,7-tetraisopropylnaphthalene was recovered from this olefin. product by recrystallization using a methanol acetone sol- Example 18 vehntl1 mixture. The 1,g,5,7detgaisoprppylgaphthaen8, A reaction was carried out similar to that set forth W 16 15 a new compoun can e 1/ as a g above except that ethylene was employed as the alkyl- 60 F 3? g q g e ps s The ating olefin. 300 grams of benzene, 0.553 millimol of P01111 0 tame can 511111 3 b6 employed. ethyl aluminum sesquichloride per mol of benzene and iobvlollsly, y modlficfltlofls d a iat ons of the 1.66 millimols of titanium tetrachloride per mol of beninvention, as hereinabove set forth, can be made withzene were employed, the reaction time was 4 hours, the out departing from the spirit and scope thereof, and theretemperature 110 C. and the initial pressure pounds fore only such limitations should be imposed as are inper square lI'lCh gauge. 355 grams of product were obdi d i h appended 1 tained, of which 28 grams were diethylbenzene, 11 grams We claim; g i lf il tetrafthyl z ifis 13 grams 1. A process for alkylating benzene which comprises i g enzene grams Po ymer and grams 70 reacting benzene with propylene in the presence of a mac 6 enzene' catalyst system consisting essentially of TiCl and an alkyl E p I aluminum sesquichloride wherein the alkyl substituent An addltional reaction was carried out s1m1lar to Exhas from one to four carbon atoms at a temperature of ample 18. Toluene was employed as the all-rylatable at least about 55 C., the total amount of catalyst emaromatlc compound, propylene as the reactant olefin and 75 ployed being at least about 0.1 millimol of catalyst per 5 mol of said benzene, with said TiCl and said alkyl aluminum sesquichloride being present in a molar ratio of about 1:1 to about 9:1.

2. A process for alky-lating benzene which comprises reacting benzene with propylene in the presence of a catalyst system consisting essentially of TiCl, and methyl aluminum sesquichloride at a temperature of at least about 55 C., the total amount of catalyst employed being at least about 0.1 millimol of catalyst per mol of said benzene, with said TiCl and said methyl aluminum sesq-uichloride being present in a molar ratio of about 1:1 to about 9:1.

3. A process for alkylating benzene which comprises reacting benzene with propylene in the presence of a catalyst system consisting essentially of TiCl and ethyl aluminum sesquichloride at a temperature or" at least about 55 C., the total amount of catalyst employed being at least about 0.1 millimol of catalyst per mol of said benzene, with said TiCl and said ethyl aluminum sesquichloride being present in a molar ratio of about 1:1 to about 9: 1.

4. A process for alkylating benzene which comprises reacting benzene with propylene in the presence of a catalyst system consisting essentially of TiCL; and isobutyl 6 aluminum sesquichloride at a temperature of at least about 55 C., the total amount of catalyst employed being at least about 0.1 millimol of catalyst per mol of said benzene, with said TiCl and said iso'outyl aluminum sesquichloride being present in a molar ratio of about 1:1 to about 9:1.

References Cited in the file of this patent UNITED STATES PATENTS 2,824,145 McCall et a1. 'Feb. 18, 1958 2,935,542 Minckler et al. May 3, 1960 2,949,492 Weaver Aug. 16, 1960 3,031,514 Kosmin Apr. 24, 1962 FOREIGN PATENTS 526,101 Italy May 14, 1955 543,259 Belgium May 30, 1956 785,314 Great Britain Oct. 23, 1957 OTHER REFERENCES Grosse et al.: J. Org. Chem. 1, 559-66 (1937). Calcott et al.: J. Am. Chem. Soc., 61, 1010-1015 (1939), p. 1012 relied on.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3 129 255 April 14 1964 Russell Go Hay et ale I It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1 line 27 for "benzes" read benzenes line 58, strike out "loe'fl first occurrence; columns 3 and 4 TABLE I under the heading "Polymefl' opposite "Example 9% for "0" read 4 opposite "Example 10" for "2" read 0 and opposite Example 11" for "4" read we 2 "0 Signed and sealed this 24th day of November 19640 (SEAL) Attest:

ERNEST W. SWIDER' EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. A PROCESS FOR ALKYLATING BENZENE WHICH COMPRISES REACTING BENZENE WITH PROPYLENE IN THE PRESENCE OF A CATALYST SYSTEM CONSISTING ESSENTIALLY OF TICL4 AND AN ALKYL ALUMINUM SESQUICHLORIDE WHEREIN THE ALKYL SUBSTITUENT HAS FROM ONE TO FOUR CARBON ATOMS AT A TEMPERATURE OF AT LEAST ABOUT 55*C., THE TOTAL AMOUNT OF CATALYST EMPLOYED BEING AT LEAST ABOUT 0.1 MILLIMOL OF CATALYST PER MOL OF SAID BENZENE, WITH SAID TICL4 AND SAID ALKYL ALUMINUM SESQUICHLORIDE BEING PRESENT IN A MOLAR RATION OF ABOUT 1:1 TO ABOUT 9:1. 